Q & A

Hull re blacking

Hellocould you please answer my question regarding re blacking the hull on a 57ft narrowboat.it has been in the water since new just under 2 years and I know it is due (blacking used "international intertuf".I think there is evidence of mill scale causing somerust areas and the hull has numerous small orange rust spots as well as lots of weed.ok to my question .from a diy point of view how should I best prepare the hull for re blacking .is jet washing then sanding it all down to bare metal the way to remove all mil scale .do you need to remove every bit of blacking on the hull above and below water line.please adviseThank youRay

Asked by: Ray Fleckney | 8.17pm, Sunday 26 June

WW says:

If you are planning to use the same finish as before, pressure jetting, scraping and wire brushing is the normal DIY method. You only need to remove any paint that is loose. If it is soundly adhered to the steel, it can be left.However, this method will not remove the mill scale. The only way to do this is to have the boat grit blasted which is a job for the professionals. Not all boatyards/dry docks will allow it because of the health hazards and mess it creates.Having got all the mill scale off, you then have the option of painting with a two part epoxy finish like Intertuf 362. These finishes can only be used on freshly grit blasted steel and should not be applied over conventional hull paint.They are more expensive than conventional one part finishes but last a lot longer so you save on the number of dry dockings you need over the life of the boat. A one part paint lasts about two years while a two part finish should last five or six years depending on the amount of use the boat gets.